This application claims the priority of Korean Patent Application No. 2002-47233, filed 9 Aug. 2002 in the Korean Intellectual Property Office (KIPO), which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a method of forming fine patterns for use in a semiconductor device, and more particularly, to a method of forming fine patterns by forming a thin silicon oxide layer on photoresist patterns before dry etching.
2. Description of the Related Art
The rapid increase in the integration of semiconductor devices results in a remarkable reduction in the size of a unit cell. A reduction in the size of a unit cell causes a reduction in the size of each of the devices formed on the unit cell. That is, the size of a transistor or a capacitor, the width of an interconnect wiring, distance between interconnect wirings, the size of a contact that electrically connects upper and lower devices are reduced.
To fabricate such a fine device, a plurality of processes are required. In particular, a photolithography technique is indispensable to precisely make fine patterns.
To perform the photolithography process, a photoresist pattern of a small critical dimension (CD) is required because of the smaller size of patterns used in fine devices. Much attention must be paid so as not to do damage to-a fine photoresist pattern during an etching process, especially during dry etching.
For instance, a photoresist pattern may be thinned or deformed. The thinning of a photoresist pattern deteriorates the pattern profile of a layer to be etched, and the deformation thereof causes problems, such as striation and/or wiggling, in a lower layer to be etched.
To solve these problems, using a multi-layered resist (MLR) or applying a polymer on a photoresist has been suggested. However, these suggestions become unfeasible as the CD of a photoresist pattern becomes smaller. Alternatively, a silicon chemical amplification of resist line (Si-CARL) process is used to solve these problems. However, this process is also not recommended because it causes excessive generation of impurities between fine patterns.